A known electronic engine control system comprises a processor-based engine controller that processes data from various sources to develop control data for controlling certain functions of the engine. One function that is can be effectively controlled by a processor-based system is engine torque. Control of torque is accomplished by control of engine fueling. A processor-based control system processes certain data useful in setting a data value for engine fueling that will cause the engine to develop requested torque, and then uses the result of that processing to control fuel injectors that inject fuel into engine cylinders where the fuel is combusted to develop the requested torque.
A processor-based engine control system can endow a diesel engine with an electronic governor, one type of which is commonly known as an all-speed governor. In general, an all-speed governor functions in a manner such that for any given speed within a range of engine speeds, fuel will be injected into the cylinders in a proper amount to handle whatever torque is being requested at that speed within a range of allowable torque. As torque requests change while engine speed is held constant at a given speed, the engine control system adjusts fueling in a manner that strives to maintain that given speed.
A motor vehicle that is powered by such an engine may have certain devices, components, and/or systems whose influence on engine torque via influencing engine fueling may be desirable under certain conditions of vehicle operation, but unnecessary and/or undesirable in the absence of those conditions. Examples are the transmission during certain gearshifts, the ABS system during certain braking events, and the traction control system during certain traction control events. When such events are allowed to influence engine torque, it is important that they do so in appropriate ways. Of particular importance is the avoidance of changing fueling to an extent that is detrimental to engine and vehicle operation. For example, fueling should not be restricted to such an extent that the engine may stall.